Objective: The aim of this study was to investigate the intestinal colonization by carbapenemase-producing enterobacteria among patients in the intensive care unit (ICU) at the University Hospital of the Faculty of Medicine of Ribeirao Preto-University of Sao Paulo (HCFMRP-USP) at Ribeirao Preto, Brazil after an outbreak of KPC-2-producing Klebsiella pneumoniae.

Methods: Ninety-four patients admitted at the ICU from June to September of 2009 were submitted to a selective culture of rectal swab specimens collected on admission and at discharge or death. However, only 135 rectal swab specimens were collected, 71 on admission and 64 at discharge from the hospital or death. Carbapenemase-producing bacteria were selected in MacConkey medium with imipenem (8 mcg/mL) or ceftazidime (32 mcg/mL). Identification and antimicrobial susceptibility profile of the isolates were performed using the Vitek® 2 System (bioMérieux). The Modifed Hodge test was used to detect carbapenemase production. PCR and sequencing was performed to investigate carbapenemases-encoding genes.

Results: Sixty-five bacterial species (48.1%) were isolated out of the 135 rectal swabs specimens evaluated. Among these, 46.1% (30/65) were identified as enterobacteria: 66.6% (20/30) K. pneumoniae, 13.3% (4/30) Enterobacter cloacae, 6.6% (2/30) Citrobacter freundii, 3.3% (1/30) Enterobacter aerogenes, 3.3% (1/30) Pantoea sp., 3.3% (1/30) Escherichia coli and 3.3% (1/30) Citrobacter youngae. All enterobacteria showed a multiresistance profile. The Modifed Hodge test was positive for 43.3% (13/20) K. pneumoniae, indicating carbapenemase production and negative to other enterobacteria. PCR amplification and sequencing identified blaKPC-2 gene in the 13 K. pneumoniae detected as carbapenemase producers but no carbapenemase-enconding gene was detected in the other 17 enterobacteria. Thus, other resistance genes may be responsible for the multiresistance profile in the last ones.

Conclusion: After control of the KPC-2-producing K. pneumoniae outbreak, isolation of these bacteria in infections was not frequent. However, this investigation showed that KPC-2-producing K. pneumoniae and other multiresistant bacteria are present in intestinal colonization of patients at the ICU and can be source of infections and dissemination of resistance genes.

Session Details

Date:

10/04/2010

Time:

00:00-00:00

Session name:

Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases